2. What is a crystal? How do minerals form? What factors affect the size and shape of crystals? What are the different crystal shapes?

3. The 5 characteristics of a mineral Natural (found in nature) Chemical composition (chemical formula) Orderly internal structure of atoms (crystal structure) Solid Inorganic (never living) Mineraloid - lacks an orderly internal structure

4. Unit 4 Crystal Formation PHENOMENON: What did you observe? What evidence do you have? OBJECTS:. What objects are interacting? MOTION /STRUCTURE Describe the structure that in the model that explains your observations copper wire and silver nitrate Salt solutions in 100% and 50% concentrations Salol cooling and crystalizing Granite rock crystals Graphite and diamonds Crystal models and crystals samples in well plate

5. Part A: Making (silver) Crystals http://www.youtube.com/watch?v=bJDeoah -Cd0http://www.youtube.com/watch?v=bJDeoah -Cd0 snowflake crystals

6. Silver nitrate ‘crystals’ pic from phone Although not flat surfaces, the silver atoms arrange in a regular repeating pattern Definition of crystal

7. How Minerals Form page 97 Magma Pressure Process Evaporation Process ( Precipitation) Process (most)

8. Part B: Concentration and Crystal Formation 1.Ions (such as salt or calcium) are dissolved in water. 2. The water EVAPORATES, and the ions form minerals such as halite, calcite, gypsum, limestone. http://www.classzone.com/books/earth_science/terc/content/inve stigations/es0506/es0506page09.cfm

9. Part C: Crystal and Space http://www.youtube.com/watch?v=HeiMfLmJtzk Mexico's Cueva de los Cristales (Cave of Crystals) contains some of the world's largest known natural crystals—translucent beams of gypsum as long as 36 feet (11 m). Volcanic activity 26 million years ago created Naica mountain and filled it with high-temperature anhydrite gypsum. When magma underneath the mountain cooled and the temperature dropped, the gypsum that had been dissolved for millions of years began to be deposited in the caves in the form of huge selenite gypsum crystals.

10. 100% concentration 25% concentration 100% concentration 25% concentration

11. Draw Particle diagrams to show (model) how the crystals formed out of a solution Salt dissolved in water 25% salt solution salt arranged into 100% concentrationcrystals Watersalt

12. White Board Session review WB is neat, organized, readable All members of the group are prepared to explain a part of the WB All group members are prepared to answer questions about the WB Address questions and answers to the entire class No judgment statements –ask good questions It’s okay to make mistakes –that’s how we learn Be respectful of the presenters. Every student is responsible for all the information learned from the discussion

13. Factors that determine crystal size: http://www.classzone.com/books/earth_scien ce/terc/content/investigations/es0506/es0506 page01.cfm?chapter_no=05 ES0506 Concentration Space Time / rate Outside inside

15. Part E: Observe crystals Under a stereoscope, compare the size of the crystals for 3 magma rocks GraniteBasaltObsidian

16. The Magma Process: (pg.97) Molten (liquid) rock in a magma chamber At, near or under earth’s surface, rises The magma begins to COOL. The atoms, ions and molecules combine to form various mineral compounds. The molecules arrange into an orderly repeating pattern to form CRYSTALS. http://www.youtube.com/watch?v=1I5Qc73o5Vkhttp://www.youtube.com/watch?v=1I5Qc73o5Vk bismuth quartz

17. Rate / Time The RATE at which the molten magma cools determines the crystal size. Predict: If the magma cools at a s-l-o-w-l-y (under the surface taking hundreds of years ) then the crystals will be… well-formed granite

18. If the magma cools quickly (weeks) the crystals will be small / microscopic / not well-formed (Look at basalt with a hand lens or scope) Predict: If the magma cools at a very fast rate, quickly, then the crystals will…. None example: obsidian a volcanic rock, cools instantly. so it has no crystal structure, but a glass-like structure

19. Crystallization of Salol Lab Slow cooling and crystalizing Quick cooling and crystalizing

20. ________: clear, whitish, transparent _______________: pink, salmon-colored ___________________: black, gray, dull ________________: black, shiny quartz Feldspar (potassium) Hornblende (amphibole ) Mica - biotite Granite contains 3-4 main minerals. Part E: Rate of Cooling and Size of crystals in Granite

21. Each mineral melts / crystallizes at its own temperature between 1300ºC and 500ºC 500°C

22. Rank the order in which the minerals in granite will crystallize. First to cool and crystallize ___________ 2 nd to crystallize ___________________ 3 rd to crystallize ___________________ Last to crystallize _________________ Hornblende (amphibole) Feldspar (potassium) - pink quartz So... Quartz is the LAST to crystallize, so it is usually shapeless. Biotite mica

23. The kind of mineral that is formed depends on… 1. Which elements are present when it forms 2. The amount of an each element present. * The same magma chamber can form different minerals.

24. Bellwork 1.What is the #1 most abundant element in the Earth’s crust. 2. List the five characteristics of a mineral: 3. What is the hardest and softest mineral on the Moh’s Scale of Hardness? 4. Define a crystal: 5. How does a fast rate of cooling affect the size of crystals? Slow rate?

25. Concentration Space Time / rate Temperature Pressure Where do diamonds form? Factors that affect the size and shape of crystals

26. The Pressure Process: 1. Rock or mineral is exposed to extremely high pressures and temperatures, and the minerals begin to break down. 2. As pressure and temperature increase, the molecules RE-FORM into new minerals! http://www.classzone.com/books/earth_science/terc/content/investigations/es0506/es0506page09.cfm

27. At what temperature and depth does graphite exist? Temp: Pressure: At what temperature and pressure do diamonds form? Temp: Pressure: Upper mantle

28. Compare the properties of a diamond and graphite Color Luster Hardness Cleavage Crystal structure

29. Graphite and diamonds are BOTH made of just CARBON atoms Make a particle diagram of the atoms graphitediamond

30. It takes Gemesis Diamond Co. four days to grow a diamond of an average size of 2.5 carats. The process begins by placing a microscopic diamond grain into a 4,000-pound machine about the size of a kitchen oven. Under hundreds of thousands of pounds of pressure and at temperatures as high as 2,700 °F, the nugget grows, one atom at a time. The Gemesis process mimics a diamond's development deep underground. Apollo Diamond, based near Boston, takes a different tack, imitating the way diamonds are made in space. Through chemical vapor deposition, Apollo's process pumps gas into a chamber that essentially rains carbon and forms a diamond nugget from a "seed" within two to four weeks time. https://www.youtube.com/watch?v=48NoIICJ2CQ Genisis diamonds Synthetic, man-made diamonds http://channel.nationalgeographic.com/channel/videos/ man-made-diamonds/ Synthetic Diamonds

31. Polymorphs. Minerals which have the same chemical make-up, but different crystal structures Both diamond and graphite contain only carbon atoms.

32. Part F: Crystal Shapes (page 99) Crystal: the orderly arrangement of the ions, atoms and molecules that determines the shape of each mineral’s crystals.

33. Potassium nitrate crystals Salt crystals http://www.classzone.com/books/eart h_science/terc/content/investigations/ es0506/es0506page05.cfm

34. Part F: Crystal Shape Activity Paper model letter Crystal name Example Mineral name Tray sample 1 2 3 4 5 6 Use table on page 99 in your text book Look at the crystal samples in the trays under the stereoscopes. Match them to the crystal models. A C F D B E Cubic Tetragonal Hexagonal Orthorhombic Monoclinic triclinic Halite (Salt) Zircon Emerald Topaz Sulfur Gypsum Mica turquoise

35. Graphing in WB’s Factors that affect crystal growth: Concentration Space Time to cool or Rate of cooling Temperature Pressure Select TWO factors and construct two graphs that show the relationship between them and crystal size and shape.

36. Example: Low concentration of material high A lot of large, well-formed crystals Few, shapeless crystals If…. Crystals had enough SPACE to form